1. Field of the Invention
The present invention relates to an organic semiconductor structure comprising an organic semiconductor layer formed with organic semiconductor material having liquid crystallinity, a manufacturing method of the same and an organic semiconductor device.
2. Description of the Related Art
As a typical example of an organic semiconductor device, an organic field-effect transistor (also called organic FET) using an organic semiconductor as an active layer (hereinafter, referred to as an organic semiconductor layer) can be mentioned. In order to realize a thin film-large area device, the organic FET is required to have uniform charge transport property over a sufficient large area.
In this organic FET, the organic semiconductor layer is formed, by vacuum deposition process, from molecular crystals represented by pentacene (see Y.-Y. Lin, D. J. Gundlach, S. Nelson, and T. N. Jackson, “Stacked Pentacene Layer Organic Thin-Film Transistors with Improved Characteristics”, IEEE Electron Device Lett, 18, 606 (1997)).
However, the organic semiconductor layers formed by the above-mentioned vacuum deposition process generally have characteristics that a large number of grain boundaries easily occur in polycrystalline state of aggregated fine crystals, and further, defects easily occur so that such grain boundaries and defects inhibit transportation of charge. Accordingly, when an organic semiconductor layer is to be formed by vacuum deposition process, it is actually very difficult to form an organic semiconductor layer serving as an element of an organic semiconductor device continuously with uniform performance over a sufficiently large area.